Cathay Pacific Airways says its profit tumbled in the first half of the year as economic weakness in China and other important markets cut passenger demand while it faced cutthroat competition from rivals.

Hong Kong's biggest airline on Wednesday posted interim net profit of 353 million Hong Kong dollars ($45.5 million), down 82 percent from the same period a year earlier.

The airline said its earnings were hurt by "economic fragility and intense competition" in the January-June period, putting sustained pressure on revenue, which fell 9.2 percent.

The company, which also operates regional carrier Cathay Dragon, said passenger numbers rose 2.7 percent but the money it earned from them fell 10 percent.

Cathay said it expects business conditions to remain challenging for the rest of the year.